Accessory and imaging apparatus

ABSTRACT

In a lens apparatus, a CS terminal is disposed adjacent to a DGND terminal, and a DCA terminal is disposed on the other side of the CS terminal from the DGND terminal. The terminals on the accessory correspond to terminals on an imaging apparatus where a CS terminal is disposed adjacent to a DGND terminal, and a DCA terminal is disposed on the other side of the CS terminal from the DGND terminal.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation, and claims the benefit, of U.S.patent application Ser. No. 16/903,243, filed on Jun. 16, 2020, which isa continuation, and claims the benefit, of U.S. patent application Ser.No. 15/992,875, filed May 30, 2018, now issued as U.S. Pat. No.10,771,670, which claims the benefit of Japanese Patent Application No.2017-108257 filed May 31, 2017, both of which are hereby incorporated byreference herein in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an accessory and an imaging apparatusthat are capable of communicating with each other.

Description of the Related Art

Accessories (accessory devices or accessory apparatuses) such as lensapparatuses that are detachably mountable to an imaging apparatusoperate by receiving supply of power from the imaging apparatus,communicating with the imaging apparatus, and so forth. Accordingly,multiple electric contacts are provided both on a mount unit of theimaging apparatus and on a mount unit of the accessory. When anaccessory is mounted to the imaging apparatus, the electric contacts atthe imaging apparatus side and the electric contacts at the accessoryside come into contact, and the imaging apparatus and the accessory areelectrically connected.

In a case where contacts, which originally should not come into contactwith each other, do come into contact in such an imaging apparatus andaccessory, a large current may flow into the imaging apparatus andaccessory. Japanese Patent Laid-Open No. 4-245872 discloses anarrangement where all output interfaces of a control unit provided tothe imaging apparatus are of the open type (open drain or opencollector). This reduces the electrical effects on the control unit in acase where contacts, which originally should not come into contact witheach other, do come into contact.

However, the output response speed of an open-type output interface isslow as compared to a CMOS-type output interface. Accordingly, it isdifficult for the imaging apparatus described in Japanese PatentLaid-Open No. 4-245872 to perform high-speed communication withaccessories.

Accordingly, it is desirable to provide an accessory and imagingapparatus capable of improving communication speed while reducingelectrical effects in a case where electric contacts are unintentionallyconnected to each other.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, an accessory,detachably mountable to an imaging apparatus and capable ofcommunication with the imaging apparatus when mounted to the imagingapparatus, includes a mount unit where a plurality of electric contactsare arrayed. The plurality of electric contacts include a first electriccontact configured to receive supply of electric power from the imagingapparatus, a second electric contact configured to set a ground level ofthe first electric contact, a third electric contact configured totransmit/receive data between the imaging apparatus and the accessory,and a fourth electric contact configured to make notification of atiming relating to communication using the third electric contact. Thethird electric contact is connected to a CMOS-type input/outputinterface. The fourth electric contact is connected to an open-typeoutput interface. The fourth electric contact is disposed adjacent tothe second electric contact on the mount unit, and the third electriccontact is disposed on the opposite side of the fourth electric contactfrom the second electric contact.

According to another aspect of the present invention, an imagingapparatus to which an accessory is detachably mountable, and which iscapable of communication with the accessory when the accessory ismounted to the imaging apparatus, includes a mount unit which is capableof coupling with the accessory, and a plurality of electric contactsarrayed at the mount unit. The plurality of electric contacts arearrayed. The plurality of electric contacts include a fifth electriccontact configured to supply electric power to the accessory, a sixthelectric contact configured to set a ground level of a first camera-sideelectric contact, a seventh electric contact configured totransmit/receive data between the imaging apparatus and the accessory,and an eighth electric contact configured to make notification of atiming relating to communication using the seventh electric contact. Theseventh electric contact is connected to a CMOS-type input/outputinterface. The eighth electric contact is connected to an open-typeoutput interface. The eighth electric contact is disposed adjacent tothe sixth electric contact on the mount unit, and the seventh electriccontact is disposed on the opposite side of the eighth electric contactfrom the sixth electric contact.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings. Each of the embodiments of the present inventiondescribed below can be implemented solely or as a combination of aplurality of the embodiments or features thereof where necessary orwhere the combination of elements or features from individualembodiments in a single embodiment is beneficial.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram describing the mutual relation between an imagingapparatus, lens apparatus, and intermediate accessory.

FIGS. 2A through 2D are schematic diagrams of mount units.

FIG. 3 is a block diagram of an imaging apparatus and lens apparatusaccording to an embodiment of the present invention.

FIGS. 4A and 4B are schematic diagrams of a camera-side contact holdingmember and an accessory side contact holding member.

FIGS. 5A and 5B are block diagrams of an imaging apparatus, lensapparatus, and intermediate accessory according to an embodiment of thepresent invention.

FIGS. 6A and 6B are block diagrams of the imaging apparatus andintermediate accessory according to an embodiment of the presentinvention, and a lens apparatus according to a conventional arrangement.

FIGS. 7A through 7E are schematic diagrams of peripheral circuits of aTYPE terminal.

FIG. 8 is a flowchart illustrating an operation flow of the imagingapparatus when the lens apparatus is mounted.

FIG. 9 is a flowchart illustrating a second communication flow.

FIG. 10 is a diagram describing a broadcast communication mode in thirdcommunication.

FIG. 11 is a diagram describing a P2P communication mode in thirdcommunication.

FIGS. 12A and 12B are diagrams describing cases where a DGND terminaland a terminal adjacent to the DGND terminal short-circuit.

FIGS. 13A through 13C are diagrams describing cases where a LCLKterminal and a terminal adjacent to the LCLK terminal short-circuit.

FIG. 14 is a disassembled perspective view of a mount mechanismaccording to a modification of the present invention.

FIGS. 15A through 15C are diagrams for exemplarily describing anon-coupled state of the mount mechanism according to the modificationof the present invention.

FIGS. 16A through 16C are diagrams for exemplarily describing a coupledstate of the mount mechanism according to the modification of thepresent invention.

DESCRIPTION OF THE EMBODIMENTS

Various types of terminology used in the specification of the presentapplication will be described prior to the description relating toembodiments of the present invention. The term “accessory apparatus(device)” (also referred to simply as “accessory”) refers to a devicethat is mountable to an imaging apparatus (image pick-up apparatus). Theimaging apparatus and accessory are mounted by coupling of mount unitsthat each has. Accessories include lens apparatuses (lens devices)having an image-taking optical system. Accessories also include anintermediate accessory mounted between a lens apparatus and the imagingapparatus body.

The term “mount unit (portion)” is a coupling unit, provided to each ofthe imaging apparatus and accessory. The mount unit of the imagingapparatus and the mount unit of the accessory each are provided withelectric contacts (electric terminals) and the electric contactsprovided to the respective mount units come into contact when theaccessory is mounted to the imaging apparatus. That is to say, the mountunits not only serve to mechanically couple the imaging apparatus bodyand accessory, but also to electrically connect the imaging apparatusbody and accessory.

Next, the mutual relation between the imaging apparatus, lens apparatus,and intermediate accessory according to an embodiment will be describedwith reference to FIG. 1. FIG. 1 illustrates the mutual relation among acamera body 100 serving as the imaging apparatus according to thepresent embodiment, a lens apparatus 200 according to the presentembodiment, intermediate accessories 400 and 500 according to thepresent embodiment, and a lens apparatus 300 according to a conventionalarrangement, which has a different configuration from the lens apparatus200 according to the present embodiment. The arrows in FIG. 1 indicatethat the devices that can be mounted to each other by coupling therespective mount units. The lens apparatus 200 has an image-takingoptical system 280, and the lens apparatus 300 has an image-takingoptical system 380. The camera body 100 has an imaging device such as acomplementary metal-oxide semiconductor (CMOS) sensor, charge-coupleddevice (CCD) sensor, or the like. A subject can be taken by mounting thelens apparatus 200 or lens apparatus 300 on the camera body 100.

The lens apparatus 200, intermediate accessory 500, and intermediateaccessory 400 can be directly mounted to the camera body 100. That is tosay, a mount unit 250 of the lens apparatus 200, a mount unit 550 a ofthe intermediate accessory 500, and a mount unit 450 a of theintermediate accessory 400, have shapes that tenable coupling to a mountunit 150 of the camera body 100.

The intermediate accessory 500 also has, besides the mount unit 550 aserving as a first accessory mount unit mountable to the camera body100, a mount unit 550 b serving as a second accessory mount unit thathas the same shape as the mount unit 150 of the camera body 100.Accordingly, the lens apparatus 200 can be mounted to the intermediateaccessory 500 as well. In other words, the lens apparatus 200 can bemounted to the camera body 100 via the intermediate accessory 500. Alsonote that another intermediate accessory (omitted from illustration) maybe mounted between the lens apparatus 200 and the intermediate accessory500. In this case, two intermediate accessories will be mounted betweenthe lens apparatus 200 and the camera body 100.

On the other hand, the shape of the mount unit 150 is such that a mountunit 350 of the lens apparatus 300 cannot be coupled thereto.Accordingly, the lens apparatus 300 cannot be directly mounted to thecamera body 100. However, the lens apparatus 300 can be mounted to thecamera body 100 via the intermediate accessory 400 that has the mountunit (first accessory mount unit) 450 a and mount unit (second accessorymount unit) 450 b that can be mounted to the lens apparatus 300. Thus,any of multiple lens apparatuses including the lens apparatus 200 andlens apparatus 300 are selectively mounted to the camera body 100.

Next, the mount units of the camera body 100, lens apparatus 200, lensapparatus 300, intermediate accessory 500, and intermediate accessory400 will be described with reference to FIGS. 2A through 2D. FIG. 2A isa schematic diagram of the mount unit 150 of the camera body 100 asviewed from the subject side, and FIG. 2B is a schematic diagram of themount unit 250 of the lens apparatus 200 as viewed from the image planeside. FIG. 2C is a schematic diagram of the mount unit 450 b of theintermediate accessory 400 as viewed from the subject side, and FIG. 2Dis a schematic diagram of the mount unit 350 of the lens apparatus 300as viewed from the image plane side.

The mount unit 150 is provided to the front side (subject side) of thecamera body 100. The mount unit 150 has a ring-shaped mount referenceface 151 for ensuring a predetermined flange focal distance. Threebayonet claws 152 a through 152 c are provided on the inner side of themount reference face 151 in the circumferential direction. A lock pin153 for positioning when bayonet-coupling the mount unit of an accessoryto the mount unit 150 is provided to the mount unit 150, so as to beretractably protruding with regard to the mount reference face 151. Whenthe mount unit 150 and the mount unit of an accessory are relativelyrotated to a position where mounting is complete, the lock pin 153engages a fitting hole provided to the mount unit of the accessory.

A camera-side contact holding member 154 is provided at a region furtheron the inner side from the bayonet claws 152 a through 152 c. Thecamera-side contact holding member 154 holds electric contacts(camera-side electric contacts) 1001 through 1012.

The mount unit 550 b of the intermediate accessory 500 has the sameconfiguration as that of the mount unit 150 illustrated in FIG. 2A.

The mount unit 250 is fixed to the rear end (image plane side) of thelens apparatus 200. The mount unit 250 has a ring-shaped mount referenceface 251 that is a reference face for flange focal distance. Threebayonet claws 252 a through 252 c are provided on the inner side of themount reference face 251 in the circumferential direction. Further, afitting face 253 is provided to the mount unit 250. The lock pin 153fits to the fitting face 253 when mounting of the lens apparatus 200 tothe camera body 100 is complete. An accessory side contact holdingmember 254 is provided at a region further on the inner side from thebayonet claws 252 a through 252 c. The accessory side contact holdingmember 254 holds electric contacts (accessory side electric contacts)2001 through 2012.

The mount unit 550 a of the intermediate accessory 500 and the mountunit 450 a of the intermediate accessory 400 have the same configurationas the mount unit 250 illustrated in FIG. 2B. That is to say, the mountunit 550 a of the intermediate accessory 500 and the mount unit 450 a ofthe intermediate accessory 400 have accessory side contact holding unitsthat hold electric contacts 2001 through 2012.

In the same way as the mount unit 150, the mount unit 450 has a mountreference face 451, bayonet claws 452 a through 452 c, and a contactholding member 454. Note however, that the length of the bayonet claws452 a through 452 c and the intervals between bayonet claws differs fromthat of the bayonet claws 152 a through 152 c of the mount unit 150.

In the same way as the mount unit 250, the mount unit 350 has a mountreference face 451, bayonet claws 352 a through 352 c, and a contactholding member 354. Note however, that the length of the bayonet claws352 a through 352 c and the intervals between adjacent bayonet clawsdiffers from that of the bayonet claws 252 a through 252 c of the mountunit 250.

Next, a case where the lens apparatus 200 is mounted to the camera body100 will be described with reference to FIG. 3. FIG. 3 is a blockdiagram illustrating a circuit configuration of a state where the lensapparatus 200 is mounted to the camera body 100. The lens apparatus 200and the camera body 100 can communicate via a communication path made upby part of the multiple electric contracts provided to the mount unit150 and mount unit 250. The lens apparatus 200 and the camera body 100can perform later-described first communication, second communication,and third communication.

A camera control unit 101 serving as a camera-side control unit controlscommunication performed between an accessory mounted to the camera body100, by controlling output of electric contacts provided to the mountunit 150, processing signals input to electric contacts, and so forth.

A camera power source unit 103 is a power source used to operate theparts of the camera body 100 and the accessory mounted to the camerabody 100. The camera power source unit 103 generates multiple differentvoltages, and supplies power source of these voltages to the parts ofthe camera body 100 and the accessory mounted to the camera body 100.

A power source switching unit 104 supplies power source to a firstcommunication interface unit 102 a. The power source switching unit 104is supplied with power source of two different voltage values from thecamera power source unit 103, and can switch the power source to besupplied to the first communication interface unit 102 a, under controlof the camera control unit 101.

A lens control unit 201 serving as an accessory side control unitcontrols communication performed between the camera body 100 and thelens apparatus 200, by controlling output of electric contacts providedto the mount unit 250, processing signals having been input to electriccontacts, and so forth.

A lens power source unit 203 generates power source of a predeterminedvoltage from the power source supplied from the camera body 100, whichis supplied to the lens control unit 201 and a lens-side communicationinterface unit 202.

The electric contact 1001 and the electric contact 2001 are terminalsused to supply power, used for control of communication performedprimarily between the camera body 100 and lens apparatus 200(communication power), from the power source unit 103 of the camera body100 to the lens apparatus 200. Hereinafter, the electric contact 1001and electric contact 2001 may also be referred to as “VDD terminal 1001”and “VDD terminal 2001”. In the present embodiment, the voltage of powersupplied to the lens apparatus 200 by the VDD terminal 1001 (hereinafterreferred to as “VDD voltage”) is 5.0 V.

The electric contact 1002 (first camera-side electric contact,corresponding to a fifth electric contact) and the electric contact 2002(first accessory side electric contact, corresponding to a firstelectric contact) are terminals used to supply power, used primarily foroperations of driving systems such as motors and the like (drivevoltage), from the camera body 100 to the lens apparatus 200.Hereinafter, the electric contact 1002 and electric contact 2002 mayalso be referred to as “VBAT terminal 1002” and “VBAT terminal 2002”. Inthe present embodiment, the voltage of power supplied to the lensapparatus 200 by the VBAT terminal 1002 (hereinafter referred to as“VBAT voltage”) is 4.5 V. The VDD terminals and VBAT terminals may becollectively referred to as “power source system terminals”.

The electric contact 1012 (second camera-side electric contact,corresponding to a sixth electric contact) and the electric contact 2012(second accessory side electric contact, corresponding to a secondelectric contact) are terminals that ground communication control systemcircuits of the camera main body 100 and lens apparatus 200. That is tosay, these are ground terminals corresponding to the VDD terminals.Hereinafter, the electric contact 1012 and electric contact 2012 mayalso be referred to as “DGND terminal 1012” and “DGND terminal 2012”.

The electric contact 1004 and the electric contact 2004 are terminalsthat ground drive system circuits including motors and so forth,provided to the camera main body 100 and lens apparatus 200. That is tosay, these are ground terminals corresponding to the VBAT terminals.Hereinafter, the electric contact 1004 and electric contact 2004 mayalso be referred to as “PGND terminal 1004” and “PGND terminal 2004”.The DGND terminals and PGND terminals may also be collectively referredto as “ground terminals”.

The electric terminal 1005 and the electric terminal 2005 are terminalsfor detecting that a lens apparatus has been mounted to the camera body100. The camera control unit 101 detects mounting and detaching of alens apparatus to and from the camera body 100 in accordance with thevoltage level of the electric contact 1005. When the camera control unit101 detects mounting of a lens apparatus, supply of power source to thelens device via the VDD terminal 1001 and VBAT terminal 1002 is started.Hereinafter, the electric terminal 1005 and electric terminal 2005 maybe also referred to as “MIF terminal 1005” and “MIF terminal 2005”.

The electric contact 1003 and the electric contact 2003 are terminalsfor distinguishing the type of accessory mounted to the camera body 100.The electric contact 1003 is pulled up to the same voltage as the powersource supplied to the camera control unit 101 within the camera body100, by a resistor 125. The electric contact 2003 is pulled down toground (DGND) via a resistor 222 within the lens apparatus 200. Thecamera control unit 101 detects the voltage value at the electriccontact 1003, and distinguishes the type of accessory mounted to thecamera body 100 based on the detected voltage value. That is to say, thecamera control unit 101 also functions as a distinguishing unit thatdistinguishes the type of accessory mounted to the camera control unit101. The camera control unit 101 also controls the power sourceswitching unit 104 so that the power source supplied to the firstcommunication interface unit 102 a by the power source switching unit104 is switched in accordance with the type of accessory mounted to thecamera body 100. Accordingly, the camera body 100 and the accessorymounted to the camera body 100 can communicate at an appropriatecommunication voltage. Hereinafter, the electric contact 1003 andelectric contact 2003 may also be referred to as “TYPE terminal 1003”and “TYPE terminal 2003”.

The electric contacts 1006 through 1008 and the electric contacts 2006through 2008 are terminals used for later-described first communication.The input/output of the electric contacts 1006 through 1008 iscontrolled by the camera control unit 101 via the first communicationinterface unit 102 a. The input/output of the electric contacts 2006through 2008 is controlled by the lens control unit 201 via thelens-side communication interface unit 202.

The electric contact 1008 and the electric contact 2008 are terminalscapable of output clock signals used for the first communication fromthe camera body 100 to the lens apparatus 200. The electric contact 1008and electric contact 2008 are also used for the lens apparatus 200 tonotify the camera body 100 of a communication standby request.Hereinafter, the electric contact 1008 and electric contact 2008 mayalso be referred to as “LCLK terminal 1008” and “LCLK terminal 2008”.The LCLK terminal 1008 is pulled up to the same potential as theinterface voltage of the first communication interface unit 102 a via aresistor 120 within the camera body 100. The LCLK terminal 2008 ispulled up to the same potential as the interface voltage of thelens-side communication interface unit 202 via a resistor 220 within thelens apparatus 200.

The electric contact 1006 and the electric contact 2006 are terminalscapable of transmitting data from the camera body 100 to the lensapparatus 200 by the first communication. Hereinafter, the electriccontact 1006 and electric contact 2006 may also be referred to as “DCLterminal 1006” and “DCL terminal 2006”. The DCL terminal 2006 is pulledup to the same potential as the interface voltage of the lens-sidecommunication interface unit 202 via a resistor 221 within the lensapparatus 200.

The electric contact 1007 and the electric contact 2007 are terminalscapable of transmitting data from the lens apparatus 200 to the camerabody 100 by the first communication. Hereinafter, the electric contact1007 and electric contact 2007 may also be referred to as “DLC terminal1007” and “DLC terminal 2007”. The DLC terminal 1007 is pulled up to thesame potential as the interface voltage of the first communicationinterface unit 102 a via a resistor 121 within the camera body 100.

Hereinafter, the LCLK terminal 1008, DCL terminal 1006, and DLC terminal1007, used in the first communication, may also be referred to as “firstcamera-side electric contact group” Also, the LCLK terminal 2008, DCLterminal 2006, and DLC terminal 2007, used in the first communication,may also be referred to as “first lens-side electric contact group”.

The electric contact 1009 and electric contact 2009 are used inlater-described second communication. The electric contact 1009 andelectric contact 2009 are terminals capable of transmitting data fromthe lens apparatus 200 to the camera body 100 by the secondcommunication. Hereinafter, the electric contact 1009 and electriccontact 2009 may also be referred to as “DLC2 terminal 1009” and “DLC2terminal 2009”. The DLC2 terminal 1009 is pulled down to the samepotential as the DGND terminal via a resistor 122 within the camera body100.

The electric contacts 1010 and 1011, and the electric contacts 2010 and2011, are terminal used in later-described third communication. Theelectric contact 1010 (third camera-side electric contact, correspondingto a seventh electric contact) and the electric contact 2010 (thirdaccessory side electric contact, corresponding to a third electriccontact) are terminals capable of bi-directionally exchanging databetween the camera body 100 and lens apparatus 200 by the thirdcommunication. Hereinafter, the electric contact 1010 and electriccontact 2010 may also be referred to as “DCA terminal 1010” and “DCAterminal 2010”. The DCA terminal 1010 is pulled up to the same potentialas the interface voltage as the second/third communication interfaceunit 102 b via a resistor 124 within the camera body 100. The DCAterminal 1010 is connected to the camera control unit 101 via aCMOS-type input/output interface. In the same way, the DCA2 terminal2010 is connected to the lens control unit 201 via a CMOS-typeinput/output interface. Accordingly, the camera control unit 101 and thelens control unit 201 can exchange data at high speeds, using the DCAterminals 1010 and 2010.

The electric contact 1011 (fourth camera-side electric contact,corresponding to an eighth electric contact) and the electric contact2011 (fourth accessory side electric contact, corresponding to a fourthelectric contact) are terminals used for notification of alater-described predetermined timing relating to third communicationbetween the camera body 100 and lens apparatus 200. Hereinafter, theelectric contact 1011 and electric contact 2011 may also be referred toas “CS terminal 1011” and “CS terminal 2011”. The CS terminal 1011 ispulled up to the same potential as the interface voltage of thesecond/third communication interface unit 102 b via a resistor 123within the camera body 100. Also, the CS terminal 2011 is pulled up tothe same potential as the interface voltage of the lens-sidecommunication interface unit 202 via a resistor 224 within the lensapparatus 200. The CS terminal 1011 is connected to the camera controlunit 101 via an open-type output interface. In the same way, the CSterminal 2011 is connected to the lens control unit 201 via an open-typeoutput interface. Note that the term “open-type output interface” heremeans an output interface that is an open drain or an open collector.

In a case where the lens apparatus 200 is mounted to the camera body 100in the present embodiment, the interface voltages of the firstcommunication interface unit 102 a and second/third communicationinterface unit 102 b are set to 3.0 V (first voltage). The interfacevoltage of the lens-side communication interface unit 202 is also set to3.0 V (first voltage). Note that hereinafter, the LCLK terminals, DCLterminal, DLC terminals, DCL2 terminals, CS terminals and DCA terminals,may be collectively referred to as “communication system terminals”.

Next, the shapes of the camera-side contact holding member 154 and theaccessory side contact holding member 254 of the mount unit 150 andmount unit 250 will be described with reference to FIGS. 4A and 4B. FIG.4A is a schematic diagram viewing the camera-side contact holding member154 and accessory side contact holding member 254 from a directionperpendicular to the optical axis, in a state where the lens apparatus200 is mounted to the camera body 100. FIG. 4B is a schematic diagramviewing the camera-side contact holding member 154 and accessory sidecontact holding member 254 from a direction perpendicular to the opticalaxis, in a state where the lens apparatus 200 is not completely mountedto the camera body 100. FIGS. 4A and 4B illustrate the camera-sidecontact holding member 154 and accessory side contact holding member 254in planar view. However, in reality, the shapes of the camera-sidecontact holding member 154 and accessory side contact holding member 254are curved following the circumferential direction of the mount unit 150and mount unit 250. Although the electric contacts of the camera body100 are illustrated in FIGS. 4A and 4B as being pins and the electriccontacts of the lens apparatus 200 as being contact pieces, anarrangement may be made where the electric contacts of the camera body100 are contact pieces and the electric contacts of the lens apparatus200 are pins.

Arrow A illustrated in FIG. 4A indicates the direction in which the lensapparatus 200 moves as to the camera body 100 (rotation direction) whendetaching the lens apparatus 200 from the camera body 100. Whendetaching the lens apparatus 200, the VDD terminal 2001 for examplecomes into contact with the TYPE terminal 1003 after having come intocontact with the VBAT terminal 1002.

Also, arrow B illustrated in FIG. 4B indicates the direction in whichthe lens apparatus 200 moves as to the camera body 100 (rotationdirection) when mounting the lens apparatus 200 to the camera body 100.When mounting the lens apparatus 200, the VDD terminal 2001 for exampleis connected to the VDD terminal 1001 after having come into contactwith the VBAT terminal 1002.

Also, the camera-side contact holding member 154 and the accessory sidecontact holding member 254 have shapes that are stepped in the opticalaxis direction, as illustrated in FIGS. 4A and 4B. The electric contacts1001 through 1004 and the electric contacts 1005 through 1012 areprovided on different tiers (or steps). In the same way, the electriccontacts 2001 through 2004 and the electric contacts 2005 through 2012are provided on different tiers (or steps). Accordingly, the electriccontacts 2001 through 2004 can be kept from coming into contact with theelectric contacts 1005 through 1012 when mounting the lens apparatus 200to the camera body 100. Accordingly, the amount of wear of the electriccontacts when mounting/detaching the lens apparatus 200 to/from thecamera body 100 can be reduced.

Further, the camera body 100 according to the present embodiment haspower source system terminals on the tier that has fewer electriccontacts. In the same way, the lens apparatus 200 according to thepresent embodiment has power source system terminals on the tier thathas fewer electric contacts. Accordingly, the amount of wear of thepower source system terminals when mounting/detaching the lens apparatus200 to/from the camera body 100 can be further reduced, and increase incontact impedance can be suppressed. As a result, stable power sourcesupply can be performed over a long time. Further note that the groundterminals also are preferably provided on the tier that has fewerelectric contacts for stable power supply.

On the other hand, the DGND terminal 1012 and DGND terminal 2012 arepreferably brought into contact with a metal portion of the mount unit150 and mount unit 250, in order to reduce the influence of staticelectricity on the internal circuits. In this case, the DGND terminal1012 is preferably situated at the end of the array of electric contacts1001 through 1012, in order to facilitate forming of the mount unit 150.In the same way, the DGND terminal 2012 is preferably situated at theend of the array of electric contacts 2001 through 2012, in order tofacilitate forming of the mount unit 250.

In light of this, the PGND terminal 1004 is provided on the tier thatholds fewer electric contacts, and the DGND terminal 1012 is provided atthe end of the array of electric contacts 1001 through 1012 in thepresent embodiment. In the same way, the PGND terminal 2004 is providedon the tier that holds fewer electric contacts, and the DGND terminal2012 is provided at the end of the array of electric contacts 2001through 2012.

Next, the order of the array of the electric contacts on the camera-sidecontact holding member 154 and accessory side contact holding member 254will be described. In the present embodiment, the PGND terminal 1004,TYPE terminal 1003, VBAT terminal 1002, and VDD terminal 1001 aredisposed on the tier of the camera-side contact holding member 154 thatholds fewer electric contacts, in order of the mounting direction of thelens apparatus 200 (direction of arrow B in FIG. 4B). In the same way,the PGND terminal 2004, TYPE terminal 2003, VBAT terminal 2002, and VDDterminal 2001 are disposed on the tier of the accessory side contactholding member 254 that holds fewer electric contacts, in order of themounting direction of the lens apparatus 200 (direction of arrow B inFIG. 4B).

If an electroconductive foreign substance is caught between thecamera-side contact holding member 154 and accessory side contactholding member 254, or an electric contact is deformed, adjacentelectric contacts may short-circuit each other. Particularly, in a casewhere the power source system terminals (VDD terminals and VBATterminals) short-circuit with the ground terminals (PGND terminals), alarge electric current will flow to the power source circuit. To counterthis, the influence of short-circuiting on the power source circuit canbe reduced by providing different electric contacts between the powersource system terminals and ground terminals.

Note that the terminals provided between the power source systemterminals and ground terminals preferably are terminals that have agenerally constant signal level during operations of the camera body 100and lens apparatus 200. Normally, a protective element, for protectinginternal circuits of the camera body 100 when short-circuiting occurs,is provided between the terminals adjacent to the power source systemterminals and the camera control unit 101. In a case where terminals ofwhich the signal level changes during operations of the camera body 100and lens apparatus 200, such as communication system terminals, areprovided between the power source system terminals and ground terminals,the wiring capacitance of these terminals will increase due to theprotective element. Accordingly, the signal waveforms transmitted orreceived through these terminals can be affected. On the other hand,terminals that have a generally constant signal level during operationsof the camera body 100 and lens apparatus 200 will be affected less byproviding the protective element. The TYPE terminals and MIF terminalsare terminals that have a generally constant signal level duringoperations, but the MIF terminals are preferably provided to the tierwhere there are more electric contacts, which will be described later,so the TYPE terminals are preferably provided between the power sourcesystem terminals and ground terminals. Note that a resistor 126 isdisposed between the TYPE terminal 1003 and the camera control unit 101as the protective element in the present embodiment.

The MIF terminal 1005 is disposed on the tier of the camera-side contactholding member 154 that has a greater number of electric contacts, at aposition that is closest to the tier with fewer electric contacts, inthe present embodiment. In a corresponding manner, the MIF terminal 2005is disposed on the tier of the accessory side contact holding member 254that has a greater number of electric contacts, at a position that isclosest to the tier with fewer electric contacts.

Disposing the MIF terminal 1005 at this position enables the MIFterminal 2005 to be the only electric contact coming into contact withthe MIF terminal 1005 when attaching/detaching the lens apparatus 200to/from the camera body 100. Accordingly, the wear on the MIF terminal1005 can be reduced. This makes defective contact of the MIF terminal1005 less readily to occur, and whether the lens apparatus is mountedcan be appropriately detected.

Note that when attaching/detaching the lens apparatus 200 to/from thecamera body 100, the MIF terminal 2005 comes into contact with theelectric contacts 1006 through 1012, so it can be said that the MIFterminal 2005 is disposed at a position where the amount of wear due tosliding is great. However, multiple types of camera accessories aremounted to the camera body 100, as illustrated in FIG. 1, and so theamount of wear of the electric contacts on the lens apparatus 200 issmall as compared to that of the camera body 100. Accordingly, theelectric contacts are arrayed in the present embodiment so that theamount of wear of the MIF terminal 1005 of the camera body 100 is small.

Further, if the MIF terminal 1005 comes into contact with other electriccontacts when mounting the lens apparatus 200 to the camera body 100,the voltage level of the MIF terminal 1005 may change and the cameracontrol unit 101 may falsely detect mounting of the lens apparatus. Ifthere is false detection of the lens apparatus 200 before mounting ofthe lens apparatus 200 is complete, power source supply by the powersource system terminals may be started, which can lead to malfunctioningof the lens apparatus 200 and affect internal circuits of the lensapparatus 200. Conversely, disposing the MIF terminal 1005 as in thepresent embodiment enables starting of power source supply before theMIF terminals are connected to each other (before completion of mountingof the lens apparatus 200) to be suppressed.

Note that the length of the MIF terminal 2005 of the lens apparatus 200in the circumferential direction of the mount unit 250 preferably isshorter than that of the other electric contacts. Accordingly, whenmounting the lens apparatus 200 to the camera body 100, the MIF terminal2005 can be made to be connected last of the multiple electric contacts.In this case, power source supply from the camera body 100 to the lensapparatus 200 can be performed after connection of the other electriccontacts has been completed. Also, when detaching the lens apparatus 200from the camera body 100, the MIF terminal 2005 can be disengaged firstout of the multiple electric contacts. In this case, supply of powersource from the camera body 100 to the lens apparatus 200 can beimmediately stopped when detaching the lens apparatus 200 from thecamera body 100. Note that it is sufficient for the length of the MIFterminal 2005 in the circumferential direction of the mount unit 250 tobe shorter than the other electric contacts by an amount equivalent of 1degree center angle.

The order of the array of the communication system terminals in thepresent embodiment is appropriately decided, taking into considerationthe roles of the terminals. Specifically, the CS terminal 1011 isdisposed adjacent to the DGND terminal 1012, and the DCA terminal 1010is disposed on the other side of the CS terminal 1011 from the DGNDterminal 1012. In the same way, the CS terminal 2011 is disposedadjacent to the DGND terminal 2012, and the DCA terminal 2010 isdisposed on the other side of the CS terminal 2011 from the DGNDterminal 2012. Accordingly, electrical influence on the camera body 100and lens apparatus 200 from unintentional connection among electriccontacts with each other is reduced, while increasing the communicationspeed of the third communication, which will be described later.

Also, the DLC2 terminal 1009 used for second communication is providedbetween the DCA terminal 1010 and the LCLK terminal 1008. In the sameway, the DLC2 terminal 2009 used for second communication is providedbetween the DCA terminal 2010 and the LCLK terminal 2008. Accordingly,electrical influence on the camera body 100 and lens apparatus 200 fromunintentional connection among electric contacts with each other isreduced, which will be described later.

Further, the first camera-side electric contact group is disposed closerto the MIF terminal 1005 than any of the DLC2 terminal 1009, DCAterminal 1010, and CS terminal 1011. That is to say, the amount ofsliding that the terminals in the first camera-side electric contactgroup experience is smaller than that at any of the CS terminal 1011,DCA terminal 1010, and DLC2 terminal 1009. Accordingly, defectivecommunication due to wear of the electric contacts is reduced, whichwill be described later.

Next, a case of mounting the lens apparatus 200 to the camera body 100via the intermediate accessory 500 will be described with reference toFIGS. 5A and 5B. The intermediate accessory 500 can perform thirdcommunication with the camera body 100.

FIGS. 5A and 5B are block diagrams illustrating a case of the lensapparatus 200 being mounted to the camera body 100 via the intermediateaccessory 500. The intermediate accessory 500 has the mount unit 550 aand mount unit 550 b, as described earlier. The intermediate accessory500 also has an accessory control unit 501 that controls communicationwith the camera body 100 and performs processing in accordance withoperation of an operating member (omitted from illustration) provided tothe intermediate accessory 500. Operation of the operating member iscommunicated to the accessory control unit 501 via an adapter operationinput unit 502. An example of an operating member is a function ring bywhich the aperture value can be set.

The mount unit 550 a is the same as the above-described mount unit 250of the lens apparatus 200. The mount unit 550 b also is the same as theabove-described mount unit 150 of the camera body 100. The electriccontacts 2001 through 2012 provided to the mount unit 550 a areconnected to the electric contacts 1001 through 1012 provided to themount unit 550 b by wiring within the intermediate accessory 500.

Note that in the intermediate accessory 500, the VDD terminal 2001 isalso connected to an accessory power supply unit 503, and is configuredso as to supply electric power to the intermediate accessory 500 aswell. In the present embodiment, the accessory power supply unit 503generates power source of 3.0 V, and supplies to the accessory controlunit 501 and adapter operation input unit 502. The DCA terminal 2010 andCS terminal 2011 used for the third communication within theintermediate accessory 500 are also connected to the accessory controlunit 501, so the intermediate accessory 500 and camera body 100 canperform the third communication.

In a case where the lens apparatus 200 is mounted to the camera body 100via the intermediate accessory 500, the interface voltage of the firstcommunication interface unit 102 a and second/third communicationinterface unit 102 b is set to 3.0 V. The interface voltage of thelens-side communication interface unit 202 also is set to 3.0 V. This sofar has been a description of a case where the lens apparatus 200 ismounted to the camera body 100.

Next, a case of mounting the lens apparatus 300 to the camera body 100will be described with reference to FIGS. 6A and 6B. The lens apparatus300 is a lens apparatus according to a conventional arrangement, asmentioned earlier, and differs from the lens apparatus 200 according tothe present embodiment. The lens apparatus 300 cannot perform the secondcommunication or the third communication with the camera body 100, butcan perform the first communication. The intermediate accessory 400 canperform the third communication with the camera body 100.

FIGS. 6A and 6B are block diagrams illustrating a case of the lensapparatus 300 being mounted to the camera body 100 via the intermediateaccessory 400. As described above, the intermediate accessory 400 hasthe mount units 450 a and 450 b. The intermediate accessory 400 also hasan adapter control unit 401 that performs processing communication withthe camera body 100, and processing in accordance with operations madeat an operating member omitted from illustration. Operations at theoperating member are notified to the adapter control unit 401 via anadapter operation input unit 402.

The mount unit 450 a is the same as the mount unit 250 of the lensapparatus 200. Note however, that the internal circuits of theintermediate accessory 400 and the internal circuits of the lensapparatus 200 are different. Specifically, the DCL terminal 2006, DLCterminal 2007, and LCLK terminal 2008, used for the first communication,are not connected to the adapter control unit 401 within theintermediate accessory 400, and are connected to the correspondingelectric contacts of the mount unit 450 b by through wiring. On theother hand, the DCA terminal 2010 and CS terminal 2011 used for thethird communication are connected to the adapter control unit 401 withinthe intermediate accessory 400. This is in order to perform the thirdcommunication between the intermediate accessory 400 and camera body100, and not perform the first communication.

The DLC2 terminal 2009 used for the second communication is pulled downto the same level as the DGND terminal 2012 via resistance within theintermediate accessory 400. This is because the lens apparatus 300 andcamera body 100 do not perform the second communication.

The TYPE terminal 2003 also is pulled down to the same level as the DGNDterminal 2012 by a resistor 422 within the intermediate accessory 400.The resistor 422 has a resistance value that is different from that ofthe resistor 222 of the lens apparatus 200.

Next the electric contacts provided to the mount unit 450 b and themount unit 350 will be described. An electric contact 3001 and anelectric contact 4001 are terminals used to supply driving power fromthe VBAT terminal 1002 of the camera body 100 to the lens apparatus 300.The VBAT terminal 2002 is connected to the electric contact 4001 bythrough wiring within the intermediate accessory 400. Hereinafter, theelectric contact 3001 and electric contact 4001 may also be referred toas “VBAT terminal 3001” and “VBAT terminal 4001”. Note that in thepresent embodiment, the voltage of power supplied to the lens apparatus300 by the VBAT terminal 1002 is 4.5 V.

An electric contact 3004 and an electric contact 4004 are terminals usedto supply communication power from the VDD terminal 1001 of the camerabody 100 to the lens apparatus 300. The VDD terminal 2001 is connectedto the electric contact 4001 by through wiring within the intermediateaccessory 400, and also is connected to an adapter power source 403within the intermediate accessory 400. The adapter power source 403generates a power source of 3.0 V as a power source to supply to theadapter control unit 401 and the adapter operation input unit.Hereinafter, the electric contact 3004 and electric contact 4004 mayalso be referred to as “VDD terminal 3004” and “VDD terminal 4004”. Notethat in the present embodiment, the voltage of power supplied to thelens apparatus 200 by the VDD terminal 1001 is 5.0 V.

An electric contact 3003 and an electric contact 4003 are terminals usedto ground the driving systems of the camera body 100 and lens apparatus300. That is to say, these are ground terminals corresponding to theVBAT terminals. The PGND terminal 2004 is connected to the electriccontact 4003 by through wiring within the intermediate accessory 400.Hereinafter, the electric contact 3003 and electric contact 4003 mayalso be referred to as “PGND terminal 3003” and “PGND terminal 4003”.

An electric contact 3008 and an electric contact 4008 are terminals usedto ground the communication systems of the camera body 100 and lensapparatus 300. That is to say, these are ground terminals correspondingto the VDD terminals. The VDD terminal 2012 is connected to the electriccontact 4008 by through wiring within the intermediate accessory 400.Hereinafter, the electric contact 3008 and electric contact 4008 mayalso be referred to as “DGND terminal 3008” and “DGND terminal 4008”.

An electric contact 3002 and an electric contact 4002 are terminals usedto detect that the lens apparatus 300 has been mounted to the camerabody 100 via the intermediate accessory 400. Upon detecting that thelens apparatus 300 has been mounted, the camera control unit 101 startssupplying power source to the lens apparatus 300. The MIF terminal 2005is connected to the electric contact 4002 by through wiring in theintermediate accessory 400. Hereinafter, the electric contact 3002 andelectric contact 4002 may also be referred to as MIF terminal 3002 andMIF terminal 4002.

Electric contacts 3005 through 3007 and electric contacts 4005 through4007 are terminals used for the later-described first communication. Theinput/output of the electric contacts 3005 through 3007 is controlled bya lens control unit 301 via a lens-side communication interface unit302. Hereinafter, the electric contacts 3005, 3006, and 3007 may also bereferred to as DCL terminal 3005, DLC terminal 3006, and LCLK terminal3007. The electric contacts 4005, 4006, and 4007 may also be referred toas DCL terminal 4005, DLC terminal 4006, and LCLK terminal 4007.

In a case where the lens apparatus 300 is mounted via the intermediateaccessory 400, the interface voltages of the first communicationinterface unit 102 a and the lens-side communication interface unit 302are set to 5.0 V (second voltage) that is the same as the voltagesupplied from the VDD terminals. The second voltage is a voltage that isdifferent from the first voltage.

On the other hand, the interface voltage of the second/thirdcommunication interface unit 102 b is set to 3.0 V. That is to say, in acase where the lens apparatus 300 is mounted to the camera body 100 viathe intermediate accessory 400, the communication voltage of the firstcommunication and the communication voltage of the third communicationare different from each other. In a case where the lens apparatus 300 ismounted to the camera body 100 via the intermediate accessory 400, thesecond communication is not performed, which will be described later.

This so far has been a description of the configuration of the camerabody 100 and of accessories that can be mounted to the camera body 100.Next, the function of the TYPE terminal 1003 will be described indetail.

An assumption will be made in the following description that the powersource voltage the TYPE terminal 1003 is pulled up to within the camerabody 100 is 3.3 V. Assumption will also be made that the resistancevalue of the resistor 125 is 100 kΩ, the resistance value of theresistor 126 is 1 kΩ, the resistance value of the resistor 222 is 33 kΩ,and the resistance value of the resistor 422 is 300 kΩ. The voltagevalue input to a TYPE_IN terminal is converted into digital signals of10-bit resolution by an AD converter that is omitted from illustration.

FIG. 7A is an illustration of peripheral circuits of the TYPE terminal1003 in a state where the lens apparatus 200 is mounted to the camerabody 100. In this case, the value input to the TYPE_IN terminal of thecamera control unit 101 is a value where the power source voltage (3.3V) has been divided by the resistor 125 and resistor 222 and A-to-Dconverted, and is approximately “0x0103”.

Also, FIG. 7B is an illustration of peripheral circuits of the TYPEterminal 1003 in a state where the lens apparatus 300 is mounted to thecamera body 100 via the intermediate accessory 400. In this case, thevalue input to the TYPE_IN terminal of the camera control unit 101 is avalue where the power source voltage (3.3 V) has been divided by theresistor 125 and resistor 422 and A-to-D converted, and is approximately“0x0300”.

Thus, the value input to the TYPE_IN terminal can be made to differ inaccordance with the type of accessory mounted to the camera body 100, bydiffering the resistance values of the resistor 422 of the intermediateaccessory 400 and the resistance value of the resistor 222 of the lensapparatus 200. Accordingly, the camera control unit 101 can distinguishthe type of accessory mounted to the camera body 100 using the valueinput to the TYPE_IN terminal.

However, in a case where there is some sort of abnormality that hasoccurred with regard to the connection state of the TYPE terminal 1003and the TYPE terminals 2003, an unanticipated value may be input to theTYPE_IN terminal. If the camera control unit 101 determines that thereis some sort of accessory mounted to the camera body 100 regardless ofsome sort of abnormality occurring in the mounting state of theaccessory, nonrated voltage may be applied to the accessory, whichshould be avoided. Accordingly, a case where some sort of abnormalityoccurs with regard to the connection state of the TYPE terminal 1003 andthe TYPE terminals 2003 will be considered with reference to FIGS. 7Cthrough 7E.

FIG. 7C is an illustration of peripheral circuits of the TYPE terminal1003 in a state where the TYPE terminal 1003 and TYPE terminal 2003 arenot in contact, even though mounting of the accessory to the camera body100 has been completed, due to faulty contact or the like. In this case,the voltage value input to the TYPE_IN terminal is decided by theresistor 125 (100 kΩ) in the camera body 100 alone, and the value afterA-to-D conversion is approximately “0x03FF”.

FIG. 7D is an illustration of peripheral circuits of the TYPE terminal1003 in a state where the TYPE terminal 1003 and the VBAT terminal 1002have short-circuited. A case will be considered here where determinationof the type of accessory mounted to the camera body 100 is performedbefore supply of power source to the VBAT terminal 1002 and VBATterminal 2002. In a case where the voltages of the VBAT terminal 1002and VBAT terminal 2002 when power source is not being supplied are thesame as that of the PGND terminals, the voltage of the TYPE terminal1003 becomes generally equal to the voltage of the PGND terminals whenthe TYPE terminal 1003 and VBAT terminal 1002 short-circuit. At thistime, the value input to the TYPE_IN terminal is decided by the ratio ofvoltage dividing by the resistor 125 (100 kΩ) and the resistor 126 (1kΩ) within the camera body 100, and is approximately “0x000A”.

Next, a case will be considered where determination of the type of theaccessory mounted to the camera body 100 is performed after supply ofpower source to the VBAT terminal 1002 and VBAT terminal 2002. In thiscase, if the TYPE terminal 1003 and the VBAT terminal 1002short-circuit, VBAT voltage (4.5 V in the present embodiment) will beapplied to the TYPE terminal 1003. The value input to the TYPE_INterminal at this time is approximately “0x03FF”.

FIG. 7E is an illustration of peripheral circuits of the TYPE terminal1003 in a state where the TYPE terminal 1003 and the PGND terminal 1004have short-circuited. In a case where the TYPE terminal 1003 and thePGND terminal 1004 have short-circuited, the voltage of the TYPEterminal 1003 is approximately equal to the voltage of the PGND terminal1004 (voltage of the reference potential for VBAT voltage). At thistime, the value input to the TYPE_IN terminal is decided by the ratio ofvoltage dividing by the resistor 125 (100 kΩ) and the resistor 126 (1kΩ) within the camera body 100, and is approximately “0x000A”.

As described above, in a case where some sort of abnormality occurs inthe connection state of the TYPE terminal 1003 and TYPE terminal 2003,the voltage of the TYPE terminal 1003 becomes generally equal to theVBAT voltage or the voltage of the PGND terminal 1004. Accordingly, therange of voltage of the TYPE terminal 1003 where determination is madein the present embodiment that a lens apparatus is properly mounted tothe camera body 100 is set to a voltage range that does not include theVBAT voltage and the voltage of the PGND terminal 1004. The Table belowis a correlation table of input values of the TYPE terminal and resultsof the camera control unit 101 distinguishing states of mounting.

TABLE TYPE_IN 0x0000 0x0080 0x0180 0x0280 0x0380 through through throughthrough through 0x007F 0x017F 0x027F 0x037F 0x03FF Determination ErrorLens — Lens Error results apparatus apparatus 200 300 Communication —3.0 V — 5.0 V — voltage

It can be seen from the Table that the camera control unit 101determines the lens apparatus 200 to be mounted to the camera body 100if the input value of the TYPE_IN terminal is in the range of “0x0080through 0x017F”. This range “0x0080 through 0x017F” does not include theinput value of the TYPE_IN terminal in a case where the voltage of theTYPE terminal 1003 is the VBAT voltage or the voltage of the PGNDterminal 1004. Accordingly, the camera control unit 101 can determinethat the lens apparatus 200 has been mounted to the camera body 100 onlyin a case where the lens apparatus 200 has been properly mounted to thecamera body 100. In a case of having determined that the lens apparatus200 has been mounted, the camera control unit 101 performs communicationwith the lens apparatus 200 using communication voltage 3.0 V.

In the same way, the camera control unit 101 determines the lensapparatus 300 to be mounted to the camera body 100 if the input value ofthe TYPE_IN terminal is in the range of “0x0280 through 0x037F”. Thisrange “0x0280 through 0x037F” does not include the input value of theTYPE_IN terminal in a case where the voltage of the TYPE terminal 1003is the VBAT voltage or the voltage of the PGND terminal 1004.Accordingly, the camera control unit 101 can determine that the lensapparatus 300 has been mounted to the camera body 100 only in a casewhere the lens apparatus 300 has been properly mounted to the camerabody 100. In a case of having determined that the lens apparatus 300 hasbeen mounted, the camera control unit 101 performs communication withthe lens apparatus 300 using communication voltage 5.0 V. Thus,determining the correlation between the input values of the TYPE_INterminal and the results of the camera control unit 101 determining thestate of mounting enables the type of mounted lens apparatus to beappropriately distinguished.

On the other hand, the camera control unit 101 determines that some sortof abnormality is occurring with regard to the mounting state of thecamera body 100 and the accessory if the input value of the TYPE_INterminal is in the range of “0x0000 through 0x007F”. This range “0x0000through 0x007F” includes the input value of the TYPE_IN terminal“0x000A” in a case where the voltages of the TYPE terminal 1003 and thePGND terminal 1004 are generally equal. In this case, the camera controlunit 101 does not communicate with the lens apparatus mounted to thecamera body. Thus, nonrated voltage can be prevented from being appliedto the accessory in a case where an abnormality has occurred in theconnection state of the TYPE terminal.

Again, the camera control unit 101 determines that some sort ofabnormality is occurring with regard to the mounting state of the camerabody 100 and the accessory if the input value of the TYPE_IN terminal isin the range of “0x0380 through 0x03FF”. This range “0x0380 through0x03FF” includes the input value of the TYPE_IN terminal “0x03FF” in acase where the voltage of the TYPE terminal 1003 and the VBAT voltageare generally equal. In this case, the camera control unit 101 does notcommunicate with the lens apparatus mounted to the camera body. Thus,nonrated voltage can be prevented from being applied to the accessory ina case where an abnormality has occurred in the connection state of theTYPE terminal.

Next, an operation flow of the camera body 100 will be described withreference to the flowchart in FIG. 8. This flow is carried out followinga computer program stored in the camera control unit 101. The flowchartin FIG. 8 starts from a state where the power source of the camera body100 is turned on by operation of a power switch of the camera body 100that is omitted from illustration. Note that steps in the flowchart areindicated by “S”.

First, the camera control unit 101 obtains the voltage value of anMIF_IN terminal in S601, and stores this in a random access memory (RAM)region that is omitted from illustration.

Next, in S602, the camera control unit 101 determines whether or not thevoltage value of the MIF_IN terminal stored in S601 is at a Low level.In a case where the voltage value of the MIF_IN terminal is not at theLow level, no lens apparatus is mounted to the camera body 100, so theflow returns to S601 (No in S602). In a case where the voltage value ofthe MIF_IN terminal is at the Low level, determination is made that alens apparatus is mounted to the camera body 100, and the flow advancesto S603.

In S603, the camera control unit 101 obtains the voltage value ofTYPE_IN, and stores this in a RAM region omitted from illustration.

Determination is made in S604 regarding whether or not the value ofTYPE_IN stored in S603 is within the range of 0x0080 or above and 0x017For below. If Yes is returned in S604, the camera control unit 101determines that the lens apparatus that has been mounted is the lensapparatus 200. In this case, the flow advances to S605.

In S605, the camera control unit 101 controls the power source switchingunit 104 so that the power supply voltage supplied to the firstcommunication interface unit 102 a is 3.0 V.

Thereafter, supply of power source to the VDD terminal 1001 by the powersource unit 103 is started in S606, and communication with the lensapparatus 200 by the first communication is started in S607.

On the other hand, in a case where No is returned in S604, the flowadvances to S608, where determination is made whether or not the valueof TYPE_IN stored in S603 is within the range of 0x0180 or above and0x02FF or below. If Yes is returned in S608, the camera control unit 101determines that the lens apparatus that has been mounted is the lensapparatus 300. In this case, the flow advances to S609.

In S609, the camera control unit 101 controls the power source switchingunit 104 so that the power supply voltage supplied to the firstcommunication interface unit 102 a is 5.0 V.

Thereafter, power source supply to the VDD terminal 1001 by the powersource unit 103 is started in S610, and in S611 the first communicationwith the lens apparatus 300 is started.

On the other hand, in a case where No is returned in S608, the flowadvances to S612. In this case, the camera control unit 101 determinesthat the accessory that has been mounted is an accessory that the camerabody 100 cannot control, or that an abnormality is occurring in themounting state, and the flow advances to S613.

In S613, the camera control unit 101 does not perform communication withthe accessory, and makes a display on a display unit, omitted fromillustration, that is provided to the camera body 100, to the effectthat a connection error has occurred.

Determination of whether or not the power source of the camera body 100has been turned off, by an operation of the power switch of the camerabody 100, is made in S614. If determination is made that the powerswitch has been turned off, processing is performed to turn the powersource off. Otherwise, the flow advances to S615.

In S615, the camera control unit 101 reads in the voltage value at theMIF_IN terminal, and stores this in a RAM region that is omitted fromillustration.

In S616, determination is made regarding whether the voltage value ofMIF_IN stored in S615 is equivalent to a High level. If the voltagevalue of MIF_IN is High, determination is made that the lens apparatuswhich had been mounted to the camera body 100 has been detached. On theother hand, in a case where the voltage value of MIF_IN is Low,determination is made that the lens apparatus remains mounted, and theflow returns to S614.

In S617, the camera control unit 101 stops communication with the lensapparatus, and in S618 supply of power source to the VDD terminal 1001by the power source unit 103 is stopped. Thereafter, the flow advancesto S601.

Next, communication performed between the camera body 100 and anaccessory mounted to the camera body 100 will be described. First, thefirst communication will be described. The first communication is onetype of communication performed between the camera body 100 and a lensapparatus mounted to the camera body 100. The first communication isperformed using the LCLK terminals, DCL terminal, and DLC terminals.Further, the first communication is carried out using aclock-synchronous serial communication method. Note that the firstcommunication may be performed using an asynchronous serialcommunication method. It that case, the LCLK terminal is used as aterminal to notify the lens apparatus of a data transmission requestfrom the camera body 100.

The lens apparatus 200 and lens apparatus 300 both handle the firstcommunication. However, the communication voltage for the firstcommunication differs between the lens apparatus 200 and the lensapparatus 300, as described earlier.

The camera body 100 transmits a control command for controlling the lensapparatus, to the lens apparatus by the first communication. The controlcommand includes commands for driving the driving units (omitted fromillustration) of the lens apparatus. Examples of driving units of thelens apparatus include a focus lens, zoom lens, and diaphragm.

The lens apparatus that has received the control command transmitted bythe first communication performs operation in accordance with thecommand. In response to the control command, the lens apparatustransmits information relating to the state of itself (stateinformation) to the camera body 100, by the first communication.Information relating to state as used here includes information relatingto position of focus lens, focal length, and aperture value. Thus, thefirst communication is communication primarily used for controlling thelens apparatus.

Next, the second communication will be described. The secondcommunication is a type of communication performed between the camerabody 100 and the lens apparatus 200 mounted to the camera body 100, andis asynchronous communication performed using the DLC2 terminals 1009and 2009. Note that the second communication is not performed when thelens apparatus 300 is mounted to the camera body 100, since the lensapparatus 300 does not have a DLC2 terminal. Accordingly, the DLC2terminal 1009 is not used in a case where the lens apparatus 300 ismounted to the camera body 100.

In the second communication, the lens apparatus 200 serves as thecommunication master, and transmits the optical data such as theposition of the focus lens, the position of the zoom lens, aperturevalue, state of the image stabilization lens, and so forth, at the lensapparatus 200, to the camera body 100. The type and order of data thatthe lens apparatus 200 transmits to the camera body 100 using the secondcommunication is specified by the camera body 100 using the firstcommunication.

Now, the flow of the second communication will be described withreference to FIG. 9. The flowchart in FIG. 9 starts from the timing atwhich imaging control is started. Note that steps are represented by Sin the flowchart.

In S1401, the camera body 100 transmits to the lens apparatus 200 astart request requesting start of the second communication, using thefirst communication. The start request transmitted in S1401 includesregistration communication commands in which the type of data that thecamera body 100 desires to receive from the lens apparatus 200 using thesecond communication, and the order of reception, are registeredbeforehand.

The lens apparatus 200 receives the start request from the camera body100 in S1411. In S1412, the lens apparatus 200 generates the types ofdata specified by the registration communication command included in thestart request, in the specified order.

In S1413, the lens apparatus 200 transmits the data generated in S1412to the camera body 100 using the second communication. That is to say,the lens apparatus 200 transmits the data generated in S1412 to thecamera body 100 using the DLC2 terminal 2009.

The camera body 100 receives the data transmitted from the lensapparatus 200 by second communication in S1402.

In a case where imaging control is started again after S1402 or S1413,the control illustrated in FIG. 9 is started again.

Thus, the start request for the second communication is made by thefirst communication, and transmission of data from the lens apparatus200 to the camera body 100 by the second communication is performedusing the DLC2 terminal 2009. Accordingly, providing the DLC2 terminal2009 separate from the electric contacts used for first communication,and performing the second communication, enables optical data to betransmitted from the lens apparatus 200 to the camera body 100 withoutinterfering with other communication that needs to be performed by thefirst communication. It should be noted that the second communicationcannot be performed if the first communication has not been established,since the start request for the second communication is given using thefirst communication.

Next, the third communication will be described. The third communicationis communication performed among the lens apparatus 200, intermediateaccessory 400, intermediate accessory 500, and camera body 100, and isasynchronous communication carried out using the DCA terminals and CSterminals.

As described earlier, the lens apparatus 300 does not have a DCAterminal or CS terminal, and so the camera body 100 and lens apparatus300 do not perform the third communication in a case where the lensapparatus 300 is mounted to the camera body 100 via the intermediateaccessory 400. However, in this case, the camera body 100 and theintermediate accessory 400 may perform the third communication.

In the third communication, the communication master is the camera body100 and the communication slaves as the lens apparatus 200, intermediateaccessory 400, and intermediate accessory 500. Although FIGS. 5A and 5Billustrate only one intermediate accessory 500 being mounted between thecamera body 100 and lens apparatus 200, there are cases where multipleintermediate accessories are mounted between the camera body 100 andlens apparatus 200. Accordingly, there are cases where multiplecommunication slaves are serially connected to one communication master.Accordingly, in the third communication, communication can be performedin a broadcast communication mode where the camera body 100 transmitssignals to the multiple slaves at the same time, and peer-to-peer (P2P)mode where a particular slave is specified and communication isperformed.

The DCA terminals both function as terminals to transmit/receive data inthe broadcast communication mode and P2P mode in the thirdcommunication. On the other hand, the functions of the CS terminalsdiffer between the broadcast communication mode and P2P mode.Hereinafter, the functions of the CS terminals in the broadcastcommunication mode and P2P mode will be described, by way of an exampleof a case where the lens apparatus 200 is mounted to the camera body 100via the intermediate accessory 500.

FIG. 10 illustrates communication control timing in broadcastcommunication exchanged among the camera control unit 101, lens controlunit 201, and accessory control unit 501. The CS terminals of the cameracontrol unit 101, lens control unit 201, and accessory control unit 501,are expressed as CS (camera), CS (lens), and CS (accessory). Also, theoutputs of the DCA terminals of the camera control unit 101, lenscontrol unit 201, and accessory control unit 501, are expressed as DCA(camera), DCA (lens), and DCA (accessory), respectively. The signalwaveform of a signal line made up of the CS terminals (CS signal line)and signal waveform of a signal line made up of the DCA terminals (DCAsignal line) are respectively denoted by CS and DCA. FIG. 10 illustratesa case of the accessory control unit 501 performing broadcastcommunication to the camera control unit 101 and lens control unit 201in response to broadcast communication performed from the camera controlunit 101 to the lens control unit 201 and accessory control unit 501.

At the timing of (1) shown in FIG. 10, the camera control unit 101 thatis the communication master outputs Low to the CS terminals, to notifythe lens control unit 201 and accessory control unit 501 that arecommunication slaves, that broadcast communication is going to bestarted. Next, at the timing of (2) shown in FIG. 10, the camera controlunit 101 outputs data to be transmitted, to the DCA terminals.

Upon detecting a start bit ST of the signal input from their DCAterminals at the timing of (3) in FIG. 10, the lens control unit 201 andaccessory control unit 501 start Low output to their CS terminals. Notethat at this point, the camera control unit 101 is already outputtingLow to the CS terminal at the timing of (1), so the level on the CSsignal line is unchanged.

When output of the data to be transmitted has been completed up to thestop bit SP at the timing of (4) in FIG. 10, the camera control unit 101releases the Low output to the CS terminal at the timing of (5). On theother hand, upon having received up to the stop bit SP, the lens controlunit 201 and accessory control unit 501 perform analysis of the receiveddata and internal processing relating to the received data. In a casewhere the internal processing has been completed, and preparation hasbeen made to receive the next data, the lens control unit 201 andaccessory control unit 501 release the Low output to their CS terminalsat the timing of (6) and (7), respectively.

Now, the amount of time required for the analysis of the received dataand internal processing relating to the received data differs dependingon the processing abilities of the individual control units.Accordingly, each control unit needs to comprehend the timing at whichthe internal processing relating to the received data has been completedat all of the other microprocessors.

Note that the CS terminals in the present embodiment are open-typeoutput terminals, as mentioned earlier. Accordingly, when all of thecamera control unit 101, lens control unit 201, and accessory controlunit 501 release the Low output to their respective CS terminals, thelevel on the CS signal line goes to High. That is to say, the controlunits that are involved in the broadcast communication can judge thatpreparation for the next communication has been made at the othercontrol units, by confirming that the level of the CS signals line hasgone to High, and accordingly can appropriately perform the nextcommunication.

At the timing of (8), the accessory control unit 501 starts Low outputto the CS terminal, to notify the camera control unit 101 and lenscontrol unit 201 that broadcast communication is going to be started.Next, the accessory control unit 501 outputs data to be transmitted tothe DCA terminal at the timing of (9).

Upon having detected the start bit ST input from their DCA terminals,the camera control unit 101 and lens control unit 201 start Low outputto their CS terminals at the timing of (10). Note that the accessorycontrol unit 501 has already started Low output to the CS terminal atthis point, so the level of the CS signal line is unchanged. Aftercompleting output of the stop bit SP at the timing of (11), theaccessory control unit 501 releases the Low output to the CS terminal atthe timing of (12).

After having received the stop bit SP input from their DCA terminals,the camera control unit 101 and lens control unit 201 perform analysisof the received data and internal processing associated with thereceived data. After preparation to receive the next data has been made,the camera control unit 101 and lens control unit 201 release the Lowoutput to their CS terminals, at the timing of (13) and (14),respectively. Thus, the CS terminals serve in broadcast communication totransmit signals to make notification of timing to start broadcastcommunication and timing that preparation for reception has beencompleted at all microprocessors. These signals are transmitted bychange in voltage value of the CS terminals.

Next, the functions to the CS terminal in P2P communication will bedescribed. FIG. 11 illustrates communication timing on P2P communicationexchanged between the camera control unit 101, lens control unit 201,and accessory control unit 501. An example will be described here whereone byte worth of data is transmitted from the camera control unit 101to the lens control unit 201, and the lens control unit 201 transmitstwo bytes worth of data to the camera control unit 101 in response tothat data.

First, the camera control unit 101 uses the DCA terminal to transmit acommand to the lens control unit 201 to cause particular data to betransmitted, at the timing of (1) shown in FIG. 11. After the timing of(2) where output has been completed up to the stop bit SP, the cameracontrol unit 101 starts Low output to the CS terminal at the timing of(3). The camera control unit 101 performs preparation to receive datawhile outputting Low to the CS terminal, and at the timing of (4) wherepreparation has been made, releases the Low output to the CS terminal.

On the other hand, after having detected the Low signal at the CSterminal output by the camera control unit 101, the lens control unit201 analyzes the command received from the camera control unit 101, andperforms internal processing relating to this command. After havingconfirmed that the Low output of the CS terminal has been released, thelens control unit 201 transmits data, corresponding to the commandreceived from the camera control unit 101, from the DCA terminal. Afterthe timing of (6) where output has been completed up to output of thestop bit SP of the second byte, the lens control unit 201 starts Lowoutput to the CS terminal at the timing of (7).

Subsequently, the lens control unit 201 releases Low output to the CSterminal at the timing of (8) where preparation for reception of thenext data has been made. Note that the accessory control unit 501, whichhas not been specified as a communication party in the P2P communicationis not involved in operation of the CS signal line and DCA signal linewhatsoever. Thus, in the P2P mode, the CS terminals transmit signals tonotify the timing at which data transmission has been completed at thedata transmitting side device, and the timing at which preparation fordata reception has been completed at the data receiving side device.These signals are transmitted by change in voltage value of the CSterminals.

As described above, in the third communication, the functions of the CSterminals different between the broadcast communication mode and the P2Pmode. This realizes the broadcast communication mode and the P2P modeusing only two signal lines. Further, transmission/reception of data inthe third communication is performed by the DCA terminals of which theinput/output interface is a CMOS type. Accordingly, high-speedcommunication can be realized even if the input/output interface of theCS terminals, which are used simply for notification of various types oftimings in the third communication, are of the open type.

Next, communication voltage of the first through third communicationwill be described. In a case where the lens apparatus 200 is mounted tothe camera body 100, the first communication, the second communication,and the third communication can be performed, as described earlier. Onthe other hand, in a case where the lens apparatus 300 is mounted to thecamera body 100, the first communication and the third communication canbe performed. That is to say, the case where the lens apparatus 200 ismounted to the camera body 100 has more types of communication to beperformed as compared to a case where the lens apparatus 300 has beenmounted. Accordingly, the communication voltage in the case where thelens apparatus 200 is mounted to the camera body 100 is preferably lowerfrom the perspective of reducing power consumption. To this end, thecommunication voltage for the first communication in a case where thelens apparatus 200 has been mounted (3.0 V) is set to be lower than thecommunication voltage in a case where the lens apparatus 300 has beenmounted (5.0 V).

Also, the configuration of the second/third communication interface unit202 b can be simplified by the communication voltage of the thirdcommunication being the same between a case where the lens apparatus 200has been mounted and a case where the lens apparatus 300 has beenmounted. At this time, the communication voltage of the thirdcommunication preferably is equal to the lower of the communicationvoltage of the first communication in a case where the lens apparatus200 has been mounted and the communication voltage of the firstcommunication in a case where the lens apparatus 300 has been mounted.Accordingly, the power consumption for performing the thirdcommunication can be reduced.

Next, the array order of electric contacts will be described, takinginto consideration the circuit configurations and roles of the electriccontacts of the camera body 100, lens apparatus 200, and intermediateaccessories 400 and 500 into consideration. As described above, drivecontrol and obtaining state information of the lens apparatus 200 andlens apparatus 300 is performed by the first communication. Accordingly,even if the second communication and the third communication cannot beperformed due to faulty contact among the electric contacts, primarycontrol of the lens apparatus 200 and lens apparatus 300 can beperformed as long as the first communication has been established.Conversely, if the first communication becomes unavailable due to faultycontact among the electric contacts, the camera body 100 can no longercontrol the lens apparatus 200 or lens apparatus 300. Accordingly, itcan be said that the electric contacts used for the first communicationare more important as compared to the electric contacts used for thesecond communication and the third communication.

Accordingly, the electric contacts are arrayed in the present embodimentsuch that the amount of wear of the first camera-side electric contactgroup due to mounting and detaching accessories is smaller than theelectric contacts 1009 through 1011 used for the second communication orthe third communication. This will be described with reference to FIGS.4A and 4B.

When mounting the lens apparatus 200 to the camera body 100, the lensapparatus 200 moves (rotates) from the position illustrated in FIG. 4Bto the position illustrated in FIG. 4A, with respect to the camera body100. At this time, each of the electric contacts held by the camera-sidecontact holding member 154 comes into the electric contacts held by theaccessory side contact holding member 254 at least once. The greater thenumber of times that an electric contact comes into contact with theelectric contacts held at the accessory side contact holding member 254,the greater the amount of wear is.

The timings at which the electric contacts 1001 through 1012 start tocome into contact with the electric contacts held by the accessory sidecontact holding member 254 during a period from starting to mount thelens apparatus 200 to the camera body 100 up to the mounting beingcompleted differ for each. For example, the DGND terminal 1012 comesinto contact with an electric contact held at the accessory side contactholding member 254 the earliest of all the electric contacts 1001through 1012 when mounting the lens apparatus 200 to the camera body100. The DGND terminal 1012 comes into contact with the electriccontacts 2005 through 2012 until mounting of the lens apparatus 200 iscomplete, so the number of times that the DGND terminal 1012 comes intocontact with electric contacts held at the accessory side contactholding member 254 is eight. On the other hand, the CS terminal 1011that comes into contact with the electric contacts held at the accessoryside contact holding member 254 next after the DGND terminal 1012 comesinto contact with the electric contacts 2005 through 2011 until mountingof the lens apparatus 200 is complete, so the number of times that theCS terminal 1011 comes into contact with electric contacts held at theaccessory side contact holding member 254 is seven, which is less thanthat of the DGND terminal 1012. Thus, when mounting the lens apparatus200 to the camera body 100, the earlier the timing of an electriccontact starting to come into contact with the electric contacts held bythe accessory side contact holding member 254 is, the greater the numberof times of contact with the electric contacts held by the accessoryside contact holding member 254 is.

In the array of electric contacts according to the present embodiment,when mounting the lens apparatus 200, the electric contacts 1009 through1011 that are used for the second or third communication come intocontact with electric contacts provided at the accessory side contactholding member 254 before the electric contacts 1006 through 1008 thatare used for the first communication. According to this array of theelectric contacts, the amount of wear of the first camera-side electriccontact group used for the first communication can be reduced ascompared to that of the electric contacts 1009 through 1011 that areused for the second or third communication. Thus, occurrence of faultycommunication due to wear of the electric contacts can be reduced.

Note that the electric contacts 2006 through 2008, which are the firstlens-side electric contact group, can be said to be disposed at aposition where the amount of wear when mounting and detaching the lensapparatus 200 to and from the camera body 100 is greater as compared tothe electric contacts 2009 through 2011. However, multiple types ofcamera accessories are mounted to the camera body 100 as illustrated inFIG. 1, and so the amount of wear of the electric contacts at the lensapparatus 200 is smaller than that at the camera body 100. Accordingly,the electric contacts are arrayed in the present embodiment so that theamount of wear of the first camera-side electric contact group issmaller, giving consideration to the electric contacts at the camerabody 100 side where the electric contacts wear more readily.

Next, the order of the array of the DGND terminal, CS terminal, and DCAterminal will be described with reference to FIGS. 12A and 12B. First, acase will be considered as a comparative example, in which the DCAterminal is disposed adjacent to the DGND terminal. The peripheralcircuits of the CS terminal, DCA terminal, and DGND terminal in thiscase are illustrated in FIG. 12A. The DCA terminal is a CMOS typeinput/output interface terminal, as described earlier. In a case wherethe DGND terminal and DCA terminal are short-circuited due to anelectroconductive foreign substance becoming lodged between the camerabody and the accessory in FIG. 12A or the like, when High level isoutput to the DCA terminal, a large current will flow from the DCAterminal toward the DGND terminal. This is because the resistance of theCMOS type interface is low when outputting High level. In this case, agreat current may flow into the accessory and the camera body that isperforming the third communication, and affect the internal circuits.

On the other hand, the CS terminal is disposed between the DCA terminaland DGND terminal in the present embodiment. FIG. 12B illustrates theperipheral circuits of the CS terminal, DCA terminal, and DGND terminalof the camera body 100 and the lens apparatus 200 serving as anaccessory according to the present embodiment. As described above, theCS terminal is an open type output terminal. Accordingly, even if theDGND terminal and CS terminal short-circuit in FIG. 12B, only a smallcurrent will flow to the DGND terminal. This is because the CS terminalis pulled up to the power source potential via a resistor. Thus, thisarrangement where the electric contact adjacent to the DGND terminal isthe CS terminal which is an open type output terminal enables electricaleffects on the internal circuits of the accessory and camera body 100 tobe reduced in a case where electric contacts are connected to each otherunintentionally.

The DLC2 terminal is disposed adjacent to the electric contact groupused for the first communication in the present embodiment. That is tosay, the DLC2 terminal is disposed adjacent to the LCLK terminal. Thereason for this will be described by way of comparison with a case wherethe CS terminal or DCA terminal used for the first communication isdisposed. Assumption will be made in the following that the lensapparatus 300 has been mounted to the camera body via an intermediateaccessory that is capable of the third communication with the camerabody. Accordingly, the communication voltage of the first communicationis 5.0 V, the communication voltage of the third communication is 3.0 V,and second communication is not performed.

FIG. 13A illustrates the peripheral circuits of the LCLK terminal and CSterminal in a case where the CS terminal is disposed adjacent to theLCLK terminal. The LCLK terminal is pulled up to 5.0 V, which is thecommunication voltage for first communication, at each of the camerabody and lens apparatus 300. On the other hand, the CS terminal ispulled up to 3.0 V, which is the communication voltage for the thirdcommunication at the camera body and the intermediate accessory. Now, ifan electroconductive foreign substance 90 becomes lodged between theLCLK terminal and the CS terminal, and the LCLK terminal and the CSterminal are short-circuited, voltage exceeding 3.0 V may be applied tothe CS terminal. At this time, voltage exceeding the operating voltage(3.0 V) will be applied to the second/third communication interface unitof the camera body and the accessory control unit of the intermediateaccessory, which is undesirable.

FIG. 13B illustrates the peripheral circuits of the LCLK terminal andDCA terminal in a case where the DCA terminal is disposed adjacent tothe LCLK terminal. The DCA terminal is pulled up to 3.0 V, which is thecommunication voltage for the third communication at the camera body andthe intermediate accessory. Now, if an electroconductive foreignsubstance 90 becomes lodged between the LCLK terminal and the DCAterminal, and the LCLK terminal and the DCA terminal areshort-circuited, voltage exceeding 3.0 V may be applied to the DCAterminal. At this time, voltage exceeding the operating voltage (3.0 V)will be applied to the second/third communication interface unit of thecamera body and the accessory control unit of the intermediateaccessory, which is undesirable.

FIG. 13C illustrates the peripheral circuits of the LCLK terminal andDLC2 terminal in a case where the lens apparatus 300 is mounted to thecamera body 100 via the intermediate accessory 400. The secondcommunication is not performed at this time, so the DLC2 terminal is notused. Accordingly, even if the LCLK terminal and the DLC2 terminal areshort-circuited, the internal circuits of the camera body 100 andintermediate accessory 400 are not readily affected in the presentembodiment.

Note that in a case where the lens apparatus 200 is mounted to thecamera body 100, the second communication is performed, but thecommunication voltage of the first communication and the secondcommunication is 3.0 V for both. Accordingly, even in a case where theLCLK terminal and DLC2 terminal are short-circuited, excessive voltagewill not be applied to the internal circuits of the camera body 100 orlens apparatus 200. According to the above, it can be said the electriccontact adjacent to the electric contact group used for firstcommunication is the DLC2 terminal not used when the lens apparatus 300is mounted.

Further, in a case where the lens apparatus 200 is mounted to the camerabody 100, the second communication and the third communication can beperformed at the same time. In this case, even if the DLC2 terminal andthe DCA terminal are short-circuited, excessive voltage will not beapplied to the internal circuits of the camera body 100 or lensapparatus 200, since the communication voltage for the secondcommunication and the third communication is 3.0 V. Accordingly, the CSterminal or DCA terminal is preferably adjacent to the DLC2 terminal.Also, the DLC2 terminal is disposed between the LCLK terminal and the CSterminal or DCA terminal in this case, so short-circuiting of the LCLKterminal and the CS terminal or DCA terminal can be made to occur lessreadily. Accordingly, short-circuiting among electric contacts thatperform communication at different communication voltages can beprevented when mounting the lens apparatus 300 to the camera body 100via the intermediate accessory 400.

Although a configuration has been described in the above embodimentwhere a device having one of a camera mount and an accessory mount isactually rotated as to a device having the other mount, therebybayonet-coupling the devices to each other, this is not restrictive. Forexample, a configuration may be employed where a camera mount andaccessory mount are relatively rotated, and the camera mount andaccessory mount are bayonet-coupled. Specifics of this will be describedin detail below.

FIG. 14 is a disassembled perspective view of a mount mechanism 5000according to a modification of the present invention. FIGS. 15A through15C are diagrams for exemplarily describing a non-coupled state of themount mechanism 5000 according to the modification of the presentinvention. FIGS. 16A through 16C are diagrams for exemplarily describinga coupled state of the mount mechanism 5000 according to themodification of the present invention. In FIGS. 14 through 16C, the lensmount 250 that is capable of bayonet-coupling to a movable mount portion5010 of the mount mechanism 5000 is also illustrated, for the sake ofdescription. Members that are the same as in the above-describedembodiment are denoted by the same reference numerals, and descriptionthereof will be omitted.

As illustrated in FIG. 14, the mount mechanism 5000 according to thepresent modification has, in order from the side to which the lens mount250 is attached, an operation portion 5030, a fixed mount portion 5020,the movable mount portion 5010, and the contact holding member 154,centered on the optical axis 3000. The operation portion 5030 is aring-shaped operating unit capable of rotating on a center axis, and isfixed to the movable mount portion 5010 by screws, by arm portions 5040.Note that in the present modification, the operation portion 5030 andmovable mount portion 5010 are fixed at two positions, using two armportions 5040 disposed in an orthogonal direction as to the center axis.According to this configuration, by the operation portion 5030 beingrotationally operated, the movable mount portion 5010 also rotatesintegrally with the center axis as the center.

Provided on the movable mount portion 5010 are movable mount claws 5011a, 5011 b, and 5011 c, that are each capable of bayonet-coupling withbayonet claws 252 a through 252 c provided to the lens mount 250. Alsoprovided to the movable mount portion 5010 is a screw portion 5012 thathas been threaded around the center axis, and the screwed state as to alater-described screw portion 5022 of the fixed mount portion 5020changes in accordance with the rotation of the movable mount portion5010 around the center axis.

The fixed mount portion 5020 has a camera mount face 5021 that comesinto contact with the mount face of the lens mount 250, and the screwportion 5022 with which the screw portion 5012 of the above-describedmovable mount portion 5010 is screwed. Unlike the above-describedmovable mount portion 5010, the fixed mount portion 5020 does not rotateon the center axis in accordance with rotation operations of theoperation portion 5030.

Next, the bayonet coupling method of the mount mechanism 5000 accordingto the present modification will be described with reference to FIGS.15A through 16C. Note that the bayonet claws provided to the lens mount250 are in a state of being capable to engage the movable mount claws5011 a through 5011 c of the movable mount portion 5010, in a state ofbeing passed through an opening portion of the operation portion 5030and an opening portion of the fixed mount portion 5020. The stateillustrated in FIGS. 15A through 15C is a state where the operationportion 5030 is situated at an unlocked position. In this state, thelens mount face of the lens mount 250 and the camera mount face 5021 ofthe fixed mount portion 5020 are in contact, but the claws of each ofthe lens mount 250 and movable mount portion 5010 do not engage eachother, and do not overlap, as viewed from the center axis direction.FIGS. 16A through 16C exemplify the mount mechanism 5000 in a statewhere the operation portion 5030 has been rotationally operated fromthis state.

The state illustrated in FIGS. 16A through 16C is a state where theoperation portion 5030 is situated in a locked position. In this state,the claws of each of the lens mount 250 and movable mount portion 5010overlap each other, and thereby are engaged in the center axisdirection. In this state, the screwing state of the screw portion 5022of the fixed mount portion 5020 and the screw portion 5012 of themovable mount portion 5010 changes in accordance with rotationaloperation of the operation portion 5030, and the movable mount portion5010 moves toward the imaging device side in the center axis direction.According to this configuration, each of the movable mount claws 5011 athrough 5011 c in a state of being engaged with the bayonet claws at thelens mount 301 side moves toward the imaging apparatus side.

As described above, the mount mechanism 5000 can move the movable mountportion in the center axis direction relative to the fixed mountportion, by rotating the movable mount portion that has claws capable ofengaging lens-mount-side claws on the center axis. According to thisconfiguration, the mount mechanism 5000 according to the presentmodification can reduce occurrence of gaps (looseness) that occursbetween the lens mount and camera-side mount in a coupled state.

Although a configuration has been described in the above modificationwhere the mount mechanism 5000 is provided to the imaging apparatusside, this can be applied to a configuration where the mount mechanism5000 is provided to a camera accessory side, such as an interchangeablelens or the like, for example.

Although a preferred embodiment of the present invention has beendescribed, the present invention is not restricted to this embodiment,and various modifications and alterations may be made within the scopeof the essence thereof. For example, a configuration may be made wherethe camera body 100 or lens apparatus 200 is not provided with the DLC2terminal.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

What is claimed is:
 1. An intermediate accessory detachably mountablebetween an imaging apparatus and a lens apparatus and the intermediateaccessory capable of communication with the imaging apparatus whenmounted to the imaging apparatus, the intermediate accessory comprising:a mount unit which is capable of coupling with the imaging apparatus;and a plurality of electric contacts arrayed at the mount unit, whereinthe plurality of electric contacts include: a first electric contactconfigured to receive supply of electric power, a second electriccontact configured to set a ground level of the first electric contact,a third electric contact configured to transmit and receive data, and afourth electric contact configured to make notification of a timingrelating to communication using the third electric contact, and whereinthe fourth electric contact is disposed adjacent to the second electriccontact on the mount unit, and the third electric contact is disposed onthe opposite side of the fourth electric contact from the secondelectric contact.
 2. The intermediate accessory according to claim 1,wherein the timing is notified by a signal transmitted using the fourthelectric contact.
 3. The intermediate accessory according to claim 1,wherein the communication using the third electric contact iscommunication performed, in a state where a plurality of accessoriesincluding the intermediate accessory are mounted to the imagingapparatus, between at least one of the plurality of accessories and theimaging apparatus.
 4. The intermediate accessory according to claim 3,wherein the communication using the third electric contact is broadcastcommunication where one of the plurality of accessories and the imagingapparatus transmits data to all the other of the plurality ofaccessories and the imaging apparatus.
 5. The intermediate accessoryaccording to claim 4, wherein the timing includes a timing to start thebroadcast communication.
 6. The intermediate accessory according toclaim 4, wherein the timing includes a timing at which preparation toreceive data has been completed at all the other of the plurality ofaccessories and the imaging apparatus.
 7. The intermediate accessoryaccording to claim 3, wherein the communication using the third electriccontact is peer-to-peer communication performed between one of theplurality of accessories and the imaging apparatus.
 8. The intermediateaccessory according to claim 7, wherein the timing includes a timing atwhich transmission of data has been completed at a data transmittingside of the one of the plurality of accessories or the imaging apparatusin the peer-to-peer communication.
 9. The intermediate accessoryaccording to claim 7, wherein the timing includes a timing at whichpreparation for reception of data has been completed at a data receivingside of the one of the plurality of accessories or the imaging apparatusin the peer-to-peer communication.
 10. The intermediate accessoryaccording to claim 1, wherein the mount unit comprises a contact holdingmember configured to hold the plurality of electric contacts, andwherein the contact holding member is provided with two tiers, each tierholding a different number of electric contacts from each other.
 11. Theintermediate accessory according to claim 10, wherein the first electriccontact, and the second through fourth electric contacts, are held ondifferent tiers of the contact holding member.
 12. The intermediateaccessory according to claim 11, wherein the number of electric contactsincluded on the tier holding the first electric contact is smaller thanthe number of electric contacts included on the tier holding the secondthrough fourth electric contacts.
 13. The intermediate accessoryaccording to claim 1, wherein the second electric contact is disposed atan end of an array of the plurality of electric contacts.
 14. Theintermediate accessory according to claim 1, wherein the third electriccontact is disposed adjacent to the fourth electric contact.
 15. Theintermediate accessory according to claim 1, wherein the mount unit hasa bayonet claw configured to couple with the lens apparatus by bayonetcoupling.
 16. The intermediate accessory according to claim 1, whereinthe plurality of electric contacts include an electric contactconfigured to receive a clock signal, an electric contact configured tobe capable of transmitting data synchronously with the clock signal, andan electric contact configured to be capable of receiving datatransmitted synchronously with the clock signal.
 17. The intermediateaccessory according to claim 1, wherein the plurality of electriccontacts include: an electric contact for determining whether or not alens apparatus is mounted to the imaging apparatus, and an electriccontact for distinguishing a type of lens apparatus mounted to theimaging apparatus.
 18. An imaging apparatus to which an accessory isdetachably mountable, and which is capable of communication with theaccessory when the accessory is mounted to the imaging apparatus, theaccessory being a lens apparatus having an optical system or anintermediate accessory mountable between the imaging apparatus and thelens apparatus, the imaging apparatus comprising: a mount unit which iscapable of coupling with the accessory; and a plurality of electriccontacts arrayed at the mount unit, wherein the plurality of electriccontacts include: a fifth electric contact configured to supply electricpower, a sixth electric contact configured to set a ground level of afirst camera-side electric contact, a seventh electric contactconfigured to transmit and receive data, and an eighth electric contactconfigured to make notification of a timing relating to communicationusing the seventh electric contact, and wherein the eighth electriccontact is disposed adjacent to the sixth electric contact on the mountunit, and the seventh electric contact is disposed on the opposite sideof the eighth electric contact from the sixth electric contact.
 19. Acamera system, comprising: an imaging apparatus; and a lens apparatusconfigured to be detachably mountable to the imaging apparatus, whereinthe lens apparatus comprising: a first mount unit where a plurality ofelectric contacts are arrayed, wherein the plurality of electriccontacts arrayed on the first mount unit include: a first electriccontact configured to receive supply of electric power from the imagingapparatus, a second electric contact configured to set a ground level ofthe first electric contact, a third electric contact configured totransmit and receive data between the imaging apparatus and the lensapparatus, and a fourth electric contact configured to make notificationof a timing relating to communication using the third electric contact,and wherein the fourth electric contact is disposed adjacent to thesecond electric contact on the first mount unit, and the third electriccontact is disposed on the opposite side of the fourth electric contactfrom the second electric contact, wherein the imaging apparatuscomprising: a second mount unit where a plurality of electric contactsare arrayed, wherein the plurality of electric contacts arrayed on thesecond mount unit include: a fifth electric contact configured to beconnected to the first electric contact and supply electric power to thelens apparatus, a sixth electric contact configured to be connected tothe second electric contact and set the ground level of a fifth electriccontact, a seventh electric contact configured to be connected to thethird electric contact and transmit and receive data between the imagingapparatus and the lens apparatus, and an eighth electric contactconfigured to connected to the fourth electric contact and makenotification of the timing relating to communication using the seventhelectric contact, and wherein the eighth electric contact is disposedadjacent to the sixth electric contact on the second mount unit, and theseventh electric contact is disposed on the opposite side of the eighthelectric contact from the sixth electric contact.
 20. A camera system,comprising: an imaging apparatus; a lens apparatus configured to bedetachably mountable to the imaging apparatus; and an intermediateaccessory configured to be detachably mountable between the imagingapparatus and the lens apparatus, wherein the intermediate accessorycomprising: a first mount unit where a plurality of electric contactsare arrayed, wherein the plurality of electric contacts arrayed on thefirst mount unit include: a first electric contact configured to receivesupply of electric power from the imaging apparatus, a second electriccontact configured to set a ground level of the first electric contact,a third electric contact configured to transmit and receive data betweenthe imaging apparatus and the intermediate accessory, and a fourthelectric contact configured to make notification of a timing relating tocommunication using the third electric contact, and wherein the fourthelectric contact is disposed adjacent to the second electric contact onthe first mount unit, and the third electric contact is disposed on theopposite side of the fourth electric contact from the second electriccontact, wherein the imaging apparatus comprising: a second mount unitwhere a plurality of electric contacts are arrayed, wherein theplurality of electric contacts arrayed on the second mount unit include:a fifth electric contact configured to be connected to the firstelectric contact and supply electric power to the intermediateaccessory, a sixth electric contact configured to be connected to thesecond electric contact and set the ground level of a fifth electriccontact, a seventh electric contact configured to be connected to thethird electric contact and transmit and receive data between the imagingapparatus and the intermediate accessory, and an eighth electric contactconfigured to connected to the fourth electric contact and makenotification of the timing relating to communication using the seventhelectric contact, and wherein the eighth electric contact is disposedadjacent to the sixth electric contact on the second mount unit, and theseventh electric contact is disposed on the opposite side of the eighthelectric contact from the sixth electric contact.
 21. A lens apparatusdetachably mountable to an imaging apparatus and capable ofcommunication with the imaging apparatus when mounted to the imagingapparatus, the lens apparatus comprising: an optical system; a mountunit which is capable of coupling with the imaging apparatus; and aplurality of electric contacts arrayed at the mount unit, wherein theplurality of electric contacts include: a first electric contactconfigured to receive supply of electric power, a second electriccontact configured to set a ground level of the first electric contact,a third electric contact configured to transmit and receive data, and afourth electric contact configured to make notification of a timingrelating to communication using the third electric contact, and whereinthe fourth electric contact is disposed adjacent to the second electriccontact on the mount unit, and the third electric contact is disposed onthe opposite side of the fourth electric contact from the secondelectric contact.